The present invention relates to a laminating press for large recreational vehicle panels and particularly to an improved clamping mechanism for the edges of a vacuum bag employed in connection with the laminating press.
The walls and ceiling of recreational vehicles, such as motor homes, trailers and the like, are laminated in large laminating presses which can manufacture up to 10'.times.40' sheets of material, which includes an outer surface, an intermediate insulated surface, and an interior panel for the recreational vehicle in very large presses. The laminating tables or presses are typically approximately 42' in length and have a width of approximately 13.5' and include up to four tiers for simultaneously laminating four panels once loaded into the laminating table. The laminating process involves laying the preglued laminate onto a fiberglass reinforced plywood (FRP) table and lowering a flexible air impervious sheet of material typically referred to as a vacuum bag, over the top of the part to be laminated and subsequently drawing a vacuum around the edges of the vacuum bag to apply even pressure on the surface of the recreational vehicle panel for a period of time sufficient to allow the adhesive employed for laminating the layers of panel together to cure. The vacuum bags provide a resilient surface which does not scratch the surface of the recreational vehicle panel and provide uniform laminating pressure across the surface of the panel, thereby effectively pressing the layers of laminate together during curing.
Existing vacuum bags used in connection with such laminating presses have edges which have been attached to a channel frame of the laminating table by the use of a backing bar and self-threading screws which extend directly through the vacuum bag material into the channel of the frame for the laminating table. As can be appreciated, with significant use of such tables, this attachment structure for the laminating press can result in tears around the edges of the fabric, reducing the effectiveness of the vacuum drawing the vacuum bag downwardly onto the part to be laminated. Replacing the vacuum bag results in numerous holes being formed into the channel frame of the laminating press. This ultimately weakens the frame, requiring its replacement. As a result of this construction, the vacuum bags of the prior art have been less than perfectly effective in forming a vacuum seal during the laminating process and their replacement has resulted in the weakening and ultimate destruction of the channel frame for the laminating press.
There exists, therefore, a need for an improved structure for attaching the vacuum bags to the laminating press of the type employed for manufacturing large panels for recreational vehicles and one which does not result in the weakening of the laminating press frame and which provides an improved vacuum seal for the bags during the laminating process.